Treatment Strategies in Colorectal Cancer Patients With Initially Unresectable Liver-only Metastases

Patients will be stratified for resectability of liver metastases (potentially resectable versus permanently unresectable), serum lactate dehydrogenase (LDH) (normal versus abnormal), BRAF mutation status (wildtype versus mutated), type of neoadjuvant chemotherapy (FOLFIRI versus FOLFOX) and hospital of registration. Patients with RAS and BRAF wildtype and left-sided primary tumors will be randomised between FOLFOX or FOLFIRI plus either bevacizumab or panitumumab. The choice between FOLFOX or FOLFIRI is to the discretion of the local investigator, however, the treatment is restricted to regimens that are specified in the protocol. Patients with RAS or BRAF mutated and/or right-sided primary tumors will be randomized between FOLFOX/ FOLFIRI (investigator choice) plus bevacizumab or 5FU, irinotecan, oxaliplatin (FOLFOXIRI) plus bevacizumab. Patients will be evaluated every 8 weeks by CT scan for disease status. The assigned systemic treatment should be continued for at least 6 months or earlier in case of resectability, progression of disease, unacceptable toxicity, or patient refusal. If after 6 months the panel concludes that the patient is still not resectable, it is highly unlikely that resectability will be achieved at all. Therefore the chemotherapy regimen may be reconsidered after 6 months of treatment. These patients should continue with the targeted drug in combination with chemotherapy, but the chemotherapy may be altered into a less toxic schedule such as fluoropyrimidine monotherapy. The targeted drug should be continued until progression or unacceptable toxicity. In patients who will become resectable and undergo secondary surgery of liver metastases, the total duration of preoperative and postoperative treatment together should be 6 months, with the chemotherapy schedule being administered according to the assigned treatment arm. However in these patients the targeted drug (bevacizumab or panitumumab) should not be continued after surgery.